Control apparatus and method for coffee grinder and brewer

ABSTRACT

A coffee grinder which has several different automatic grinding capacities is connected to a coffee brewer which has several different automatic brewing capacities by a control that inhibits brewing of all but the corresponding brew capacity following grinding of a quantity of coffee. The grinder is also inhibited from grinding any more coffee until the appropriate brew cycle of the coffee brewer is started. Once the corresponding brewing cycle is selected, the coffee grinder is reset and any grinding capacity may be selected. A calibration mode for the coffee grinder and the coffee brewer is provided wherein the duration of the grinding cycle or brewing cycle, respectively, is set by manually initiating the cycle and then halting of the cycle when the appropriate capacity is reached. The duration of the cycle is then set for subsequent automatic operation.

This is a division of application Ser. No. 08/386,464, filed Feb. 10,1995, now pending.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a control method andapparatus for a coffee grinder and for a coffee brewer, and moreparticularly, to an interface between a coffee grinder and brewer toselectively provide interlocked operation, and to provide calibrationduring set up of the respective grinder and brewer.

2. Description of the Related Art

Coffee bean grinders often have automatic controls which provide forgrinding of a predetermined measure of ground coffee beans when a grindstart switch is operated. Grinders for large volume operation, such asin commercial kitchens, have the ability to grind several differentquantities of coffee beans automatically. For example, a commercialcoffee grinder may have a switch that causes automatic grinding of aquantity of coffee for 12 cups of brewed coffee, a second switch thatcauses a quantity of coffee for 24 brewed cups to be ground, and a thirdswitch for 36 cups of brewed coffee. Operation of one of these switchescauses the desired quantity of beans to be ground into a filter basket,for example.

Coffee brewers which automatically brew a set quantity of coffee arealso known. These coffee brewers are connected to water supply lines,such as municipal water lines, and automatically measure out theappropriate quantity of water for the coffee to be brewed. In commercialcoffee brewers, plural brewing capacities are provided. An automaticcoffee brewer for use with the above-described coffee grinder has aswitch for brewing 12 cups of coffee, a second switch for brewing 24cups, and a third switch for brewing 36 cups. Of course, othercombinations of capacities are possible as well. It is noted that thereference to cups in relation to coffee brewers may not mean an 8 ouncecup, but typically refers to a 6 ounce coffee cup.

In kitchens having such multiple capacity coffee grinders and coffeebrewers, the appropriate brew cycle must be selected for the quantity ofcoffee beans ground during the grind cycle. Due to human error, such asa result of the kitchen staff being distracted or too long a timepassing from grinding of the coffee to starting of the brew cycle, abrew cycle that does not match the quantity of ground coffee may beselected. This results in coffee that is either too strong or too weak.Not only must this coffee be disposed of, resulting in costly waste, butanother pot of coffee must then be brewed and customers are often leftwaiting while this second pot, hopefully of the appropriate strength, isbrewing.

During set-up of automatic coffee grinders and coffee brewers, operationtimes for the grind and brew cycles, respectively, most be set. Forexample, automatic coffee brewers that are connected to a municipalwater supply determine the amount of water to use during the brew cycleby timing the opening of a valve. Variations in water pressure from onelocation to another can cause a different amount of water to be admittedfor a certain opening time of the valve. Adjustments of the valveopening time are made on a trial and error basis until the correctquantity of water is used for the brew cycle, each time running a cycle,measuring it, and adjusting the quantity and repeating this until thecorrect quantity is dispensed.

Coffee grinders also use timers to determine the length of the grindcycle. Variations in coffee bean strength, quality, roast, or whetherthe coffee is decaffeinated or not, need to be taken into considerationin setting the grind cycle time. Adjustments in the grind time are alsodone on a trial and error basis in the known automatic coffee grinders.

SUMMARY OF THE INVENTION

An object of the present invention is to permit only a proper brewingcycle to be run for a corresponding quantity of ground coffee that hasbeen ground during an associated grind cycle.

Another object of the invention is to provide easy calibration of agrinder cycle and of a brewer cycle for coffee.

A further object of the invention is to provide a control for a coffeegrinder and for a coffee brewer which permits the coffee grinder and thecoffee brewer to be connected for interlocked operation and to beselectively disconnected from one another for stand alone operation.

Another object is to provide a safe, low voltage, isolated communicationlink between associated devices, such as coffee grinders and coffeebrewers.

Yet another object of the invention is to provide a simple, digitalcommunication link between equipment.

These and other objects and advantages of the invention are provided bya control for a coffee grinder having a plurality of grinding capacitiesand a coffee brewer having a plurality of brewing capacities, includinggrind sensor means in the coffee grinder for sensing occurrence of agrind event and for sensing which of the plurality of grindingcapacities has occurred in the grind event, the grind event beinggrinding of a predetermined quantity of coffee corresponding to aselected one of the plurality of grinding capacities; grind controlmeans in the coffee grinder for generating a grind signal correspondingto the selected one of the plurality of grinding capacities thatoccurred in the grind event sensed by the grind sensor means; acommunication link connected to the grind control means to carry thegrind signal; and a brew control means in the coffee brewer andconnected to the communication link for inhibiting all of the pluralityof brewing capacities but one brewing capacity corresponding to thegrind event until the one brewing capacity is selected in the coffeebrewer.

The control includes a brew sensor means in the coffee brewer forsensing selection of the one brewing capacity; the brew control meansincluding means for generating a brew signal on the communication linkto the grind control means when the one brew capacity is sensed by thebrew sensor means; and the grind control means including means forinhibiting all subsequent grinding events by the coffee grinder afteroccurrence of a grinding event until a brew signal is received by thegrind control means.

When the communication link is disconnected, the grinder and the brewerautomatically operate as stand alone units. Interconnected operation isonce again established when the communication link is reconnected.

Several brewers may be connected in one loop to a grinder with littlemore effort required than providing additional two wire connections.

The invention provides a control apparatus and method which is notlimited to any particular type of equipment, but can be used in otherapplications as well. For example, ice dispensers and drink dispenserscould be connected.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a coffee grinder and a coffee brewerconnected of interlocked operation according to the principles of thepresent invention;

FIG. 2 is a block diagram of the coffee grinder and the coffee brewerwith the interlock communication link of the invention;

FIG. 3 is a flow chart showing the operation of either the grinder orthe brewer;

FIG. 4 is a flow chart of the grinder run mode, or interlocked mode,operation;

FIG. 5 is a flow chart of the brewer run mode, or interlocked mode,operation;

FIG. 6 is a flow chart of the grinder program mode, or calibrate mode,operation;

FIG. 7 is a flow chart of the brewer program mode, or calibrate mode,operation;

FIG. 8 is a flow chart of the stand alone operation of either the coffeegrinder or the coffee brewer;

FIG. 9 is a circuit diagram of a first portion of the grinder controlcircuit according to a preferred embodiment of the present invention;

FIG. 10 is a circuit diagram of a second portion of the grinder controlcircuit of FIG. 9;

FIG. 11 is a circuit diagram of a first portion of the brewer controlcircuit according the a preferred embodiment of the invention;

FIG. 12 is a circuit diagram of a second portion of the brewer controlcircuit of FIG. 11; and

FIG. 13 is a timing diagram showing the signals carried on thecommunication link of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIG. 1 is shown a coffee grinder 20 and coffee brewer 22 connectedfor interlocked operation according to the present invention. The coffeegrinder 20 has two compartments 24 and 26 for storing whole beans, ascan be seen through a window 28. Although any type of coffee may bestored in the two compartments, the most common use of such twocompartment grinders is that one compartment 24 holds regular coffeebeans and the other compartment 26 holds decaffeinated coffee beans. Agrinder housing 30 includes several size selection switches on the frontpanel, including for example, a 12 cup regular selection switch 32, a 24cup regular selection switch 34, a 36 cup regular selection switch 36,and 12, 24, and 36 cup selection switches 38, 40, and 42, respectively,for the decaffeinated coffee. The lower portion of the grinder housing30 has a filter basket holder 44 in which is shown a filter basket 46. Apower switch 48 is provided on the front panel.

The coffee brewer 22 of the illustrated embodiment includes a brewhousing 50 having two brewers with respective brew baskets 52 and 54above two coffee canisters 56 and 58. Each canister 56 and 58 has a tapspout 60 and 62 and a vertical level indicator tube 64 and 66 whichshows in a glass sight the level of the coffee in the canister. Beloweach canister 56 and 58 is a warmer (which is not visible in the view ofFIG. 1). A hot water tap 68 extends from the lower front of the housing50.

The top portion of the brew housing 50 includes a number of brew sizeselection switches, including, for example, a 12 cup brew switch 70, a24 cup brew switch 72, and a 36 cup brew selection switch 74 for theleft hand brewer, and a similar arrangement of a 12 cup brew switch 76,a 24 cup brew switch 78, and a 36 cup brew selection switch 80 for theright hand brewer. Each of the switches 70-80 shown in the drawing is alighted switch for the sake of clarity in the drawing, although it maybe preferable in some instances to provide a separate light for eachswitch, such as above or below each switch. In addition, the front panelincludes a power switch 82, on/off switches 84 and 86 for each of thewarmers, and a hot water dispense switch 88 which controls the flow ofhot water from the hot water tap 68.

A communication link 90 extends between the coffee grinder 20 and thecoffee brewer 22. The communication link 90 is removable by beingdisconnected at each end from the grinder 20 and brewer 22. When thecommunication link is removed, the grinder 20 and brewer 22 operate asstand alone units.

Operation of the Interlock Control

A functional block diagram of the interlock control for the presentsystem is shown in FIG. 2. In the grinder 20 is a microprocessor 100which is connected to a receive circuit 102 that inputs data to themicroprocessor 100 from the communication link 90 and a transmit circuit104 that outputs data from the microprocessor 100 to the communicationlink 90. The receive circuit 102 and the transmit circuit 104 includeoptical couplers in the preferred embodiment. The communication link 90in the present embodiment is a current loop and is, therefore, connectedto a constant current source 106 in the grinder 20. The current loop, ofcourse, includes the positive and ground leads, as shown. In the breweris also a microprocessor 108, which communicates over the communicationlink 90 through a transmit circuit 110 and a receive circuit 112.

The connection of additional brewers to the grinder is easilyaccomplished by connecting them into the current loop so that theyreceive the grinder size pulses and have an opportunity to transmitacknowledgement pulses, as will be discussed in conjunction with FIG.13.

A flowchart of the overall operation of either the grinder or the brewercontrol is shown in FIG. 3. The same process steps apply to both. Thefirst block 120 refers to the power-up of the control when power isapplied to the grinder or brewer unit. After initialization of thecontrol circuit, a decision is made at block 122 as to whether thecurrent loop of the communication link is open and has been so for somespecified period of time. If the answer is yes, the control unit isswitched to stand alone operation, as indicated by block 124. The standalone operation of the grinder and the brewer is set out in greaterdetail hereinafter in conjunction with FIG. 8.

If the current loop of the communication link is found not to be openafter the specified period of time in the block 122, the unit isswitched to interlock operation, as indicated by block 126. Theinterlocked operation of the brewer and of the grinder are each set outin greater detail hereinbelow in conjunction with FIGS. 4 and 5.

Following the stand alone operation 124 and the interlocked operation126, the communication line is checked at block 128 for signals. Inother words, the control unit checks the receive unit on thecommunication link. After checking for data on the communication link atthe block 128, the process returns to the decision block 122 to checkwhether the communication link has been disconnected. The processembodied in the flowchart of FIG. 3, as in the following flowcharts, isimplemented by programming the processor in the appropriate softwarelanguage according to known programming techniques.

The interlocked operation, also referred to as run mode, of the grinderis illustrated in the flowchart of FIG. 4. The first block 130 referredto as run mode initiates the operation of the grinder. A firstdetermination is made at block 132 to determine whether a run switchinside the grinder housing is switched from a run position to a program,or calibrate, position. If in the program position the process goes tothe program mode, which will be described later, at block 134. If, onthe other hand, the mode switch is in the run mode, the selector switchinputs are read at block 136. The selector switches are the controls onthe front panel of the grinder by which the user selects the grindcapacity, and as in the present example, the type of coffee to beground. If a size selection via the switches has not been made, asdetermined at block 138, then a signal is transmitted on thecommunication link that no size is pending, as shown at block 140. Theprocess returns to the decision block 132, and awaits a size selection.

Once a size selection is made by the user, the selected size grindingcycle is run at block 142. This involves operation of the auger motorand the grinding motor for the predetermined time interval. A signalcorresponding to the selected size is transmitted over the communicationline at block 144. After transmission of the size signal at block 144,the communication link is checked for an acknowledgement signal from thebrewer that the corresponding brew cycle is selected, as shown at theblock 146. If the acknowledgement has not been received, as determinedat block 148, the size signal is once again transmitted at the block144. The process continues in this loop until the acknowledgement isreceived, which prevents the grinder from reading the selector switchesfor further grind selections.

When the acknowledgement is received, at the block 148, the process isreturned to the block 132 at the beginning of the flowchart. Theacknowledgement indicates that the brewer has been started, as will bediscussed hereinafter.

In FIG. 5 is shown the interlocked run mode operation of the brewer. Therun mode begins at block 150, after which a determination is made atblock 152 as to whether the program/run mode switch is in the run mode.If the switch is not in the run mode, then the switch is set for theprogram mode, as shown at block 154. The program mode will be discussedhereinafter. If at the decision block 152 the determination is made thatthe mode switch is in the run position, the process proceeds to checkthe receiver for the data on the communication link, at block 156. Theprocess is looking for information from the grinder indicating that aquantity of coffee has been ground and what that quantity is.

If, after checking the communication link, the processor finds a signalindicating "no size pending," as determined at block 158, the processreturns to the block 152. The "no size pending" signal indicates that noquantity of coffee beans has been ground, and so the brewer is, ineffect, waiting for the coffee to be ground. If the decision block 158finds some size, or quantity, signal on the communication link, theprocess continues on to block 160 where the determination is again madeas to the status of the mode switch. Again, if the mode switch is not inthe run mode, the processor returns to the program mode, at the block154. If yes, the process continues to block 162 where a size indicatoron the front panel of the brewer corresponding to the size signalreceived on the communication link is energized. In other words, if thesize signal received in step 156 from the grinder indicates that coffeebeans for 24 cups has been ground, then the processor illuminates theindicator light showing that 24 cups are to be brewed.

For the sake of convenience, it is preferred that the illuminatedindicator either be immediately adjacent the corresponding, i.e., 24cup, brew start switch, or that the brew start switch itself illuminate.That tells the operator which quantity of coffee beans has been groundand which quantity of coffee is to be brewed from the ground beans.Other indicator means are, of course possible, including, for example,an LCD (liquid crystal display) panel or other alpha numeric display fordisplaying the size to be brewed. While not as intuitive as a lightedindicator adjacent the brew switch to be selected, this would have theadvantage of displaying additional information as well.

The process block 164 indicates that the processor reads the brew startswitches, also termed selector switch inputs, for an input. Theprocessor is waiting for the operator to select a brew cycle. At block166, the determination is made as to whether the brew cyclecorresponding to the one indicated at the block 162, and to the quantityof coffee beans ground, has been selected by the operator. If not, thereceiver is again checked, at block 168, for a size signal. As above, ifthe signal on the communication link is found to be a "no size pending"signal as determined at block 170, then the indicator light is turnedoff, at block 172. If instead, a size signal is found on thecommunication link at the block 170 and the corresponding size brewcycle has yet to be selected as determined at the block 166, then theprocess returns to the block 160 to continue lighting the correspondingsize indicator lamp on the brewer and waiting for the appropriate brewcycle switch to be selected.

Returning to the block 166, if the proper cycle is selected then anacknowledgement signal is forwarded on the communication link via thetransmitter at the block 174. The process continues as the selected brewcycle is run by the brewer, at block 176. Thus, only the proper amountof coffee is brewed from the quantity of beans that were freshly ground.Once the brew cycle is completed, the indicator light can be turned off,at the block 172, and the process returns to the initial steps at theblock 152.

Thus, there is shown and described an interlock control for a coffeegrinder and coffee brewer, which assures that the proper quantity ofcoffee is brewed each time for the quantity of beans that are ground.

Learn Mode Operation

The present invention also incorporates a learn mode feature providingeasy set-up and calibration regardless of variations in environmentalconditions. In FIG. 6 is set out the calibration process, also referredto as a programing mode, for the coffee grinder. The program, orcalibrate, mode is entered, at block 180, from the grinder run processshown in FIG. 4. A determination is made at block 182 as to whether themode switch in the grinder is still in the program mode or whether ithas been changed to the run mode. An operator or installer, such asduring set up of the grinder switches the run/program switch to theprogram mode to calibrate the grinder. If the run/program switch isstill in the program mode, the calibration process continues at block184 by reading the selector switches of the grinder. If the selectorswitch is not being pressed by the operator, the block 186 returns theprocess to the block 182. If, on the other hand, one of the selectionswitches is being operated, then the calibration begins at block 188.The operator places a coffee quantity measure vessel under the grinderoutput to catch the ground coffee beans as it is being ground. First,the grinder is energized at block 190 so that the grinding of the coffeebeans begins. A counter in the control circuit of the grinder isinitialized at block 192 and incrementing of the counter is begun atblock 194. After one increment of the counter, which here is acting as atimer, the selection switch is checked at block 196 to determined if itis still being pressed. If the operator watching the measure vessel fillsees that it has filled to the desired level, the operator releases theselection switch. If the measure vessel is not yet filled to the desiredlevel, the operator continues to press on the selector switch, so thatthe process is returned to the block 194 for further incrementing of thecounter. When the measure is filled to the desired level, which dependson the strength and type of coffee desired, the operator releases theselection switch and the process continues to block 198, where thegrinder is turned off. The count reached by the counter, which indicatedthe length of time required for the grinder to grind the desire quantityof coffee, is stored in RAM (random access memory) at block 200. Theblock 202 then indicates that the end of the calibration cycle, at leastfor this selection switch, has been reached and returns the process tothe block 180.

In one embodiment, a top-off feature is provided. Since the brewedcoffee depends more on the weight of the ground beans than on thevolume, the user conducting the calibration can stop the calibrationprocess at the block 198 when the quantity of ground beans is believedto be correct. The ground beans may then be weighed or otherwisemeasured. An additional amount of ground beans may then be added by onceagain pressing the same selection switch to "top-off" the quantity ofgrounds. The count for this additional amount is added onto the originalcount, and the process continues.

The foregoing description has only detailed a single pass through thecalibration cycle during which the grinding time for a single selectionswitch was set. Each selection switch must be individually calibrated,so in the illustrated embodiment of FIG. 1 the calibration cycle must berun six times, one for each of the size selection switches. While it maybe possible to, for example, calibrate the 24 cups switch on the regularcoffee side of the grinder and then have the same calibration settingapply for the 24 cup decaffeinated switch, the regular and decaffeinatedcoffees may be of different strengths and so require different grindingtimes to compensate. Of course, if it is desired, the calibration timefor one side may be applied to the corresponding selection switch of theother side of the two sided grinder. It is also possible to calibratethe grinder to the 12 cup capacity and then to multiply the grind timeby the appropriate amount for the 24 and 36 cup capacity switches, forexample, thereby avoiding repeated calibration cycles.

Referring again to FIG. 6, if the run program switch is determined atthe block 182 to be in the run position, then a determination is made atblock 204 as to whether any changes have been made in the calibrationtimes by comparing the values stored in RAM at block 200 to values inthe permanent memory of the grinder control. If no changes were made,the process returns to the run mode at block 206. If changes are found,then the new counter values in the RAM are stored in the non-volatilememory (NVM), at block 208. In some embodiments, the new values arealways written to the non-volatile memory without checking for changes.The process then returns to run mode.

The process steps for calibration of the brewer are shown in FIG. 7. Thecalibration of the brewer is important since it is connected directly toa municipal water supply, for example, and water pressure can vary fromone supply to another. The quantity of coffee being brewed is determinedby the amount of time that the water valve is open. Thus, the brewermust be set up to admit the correct quantity of water for the waterpressure and flow rate of the particular installation. As in the grindercalibration, the programming of the brewer begins at block 210 with atransfer from the run process of FIG. 5 to the program mode of FIG. 7.In the first step at block 212, the brew indicators are all flashed toindicate the program mode. The position of the run/program switch ischecked at block 214, and if found to still be in program position, theselector switches are read at block 216.

The operator seeking to calibrate the brewer would place a measuringvessel below the brew output and press one of the brew select switches.If, at block 218, no select switch is yet pressed, the process returnsto the block 214. If the operator has pressed one of the selectionswitches, the calibration process is started at block 220. The selectionswitches which were not selected by the operator cease flashing at block222, and the solenoid which operates the water valve is operated atblock 224. Once the solenoid opens the water valve and the water beginsto flow into the measuring vessel, the counter is initialized at block226 and incrementing of the counter begins at block 228.

The operator waits until the measuring vessel has filled to the desiredamount, for example, 24 cups of water, and again presses the brew selectswitch that is being calibrated. If this switch has not yet beenpressed, as determined at block 230, the process returns to the block228 to increment the counter. When the selection switch is again closed,the process continues to block 232 to turn off the water valve byde-energizing the solenoid. The count attained by the counter is storedin RAM at block 234 and the calibration of that selection switch iscompleted at block 236 so that the-next selection switch may becalibrated. The programming sequence starts over at the block 212.

Once all brew size selection switches have been calibrated, theprogram/run switch is changed to the run position as determined at theblock 214, and the flashing of the indicator lights is stopped at block238. The determination is made as to whether any changes have been madein the timing of the valve openings by comparing the contents of the RAMto a non-volatile memory at block 240. If no changes have been made, theprocess is returned to the run mode at block 242, but if changes havebeen made they are written into the non-volatile memory (NVM) at block244 and then the process returns to the run mode. As above, the newvalues may be written in any event.

The grinder and brewer are, therefore, both calibrated to brew thecorrect strength of coffee without the trial and error set up requiredof earlier devices.

Stand Alone Operation

When the communication link between the coffee grinder and the coffeebrewer is disconnected, each unit operates as a stand alone unit. Thegrind and brew cycles may be started at any time independently of oneanother. FIG. 8 illustrates the stand alone operation of either thegrinder or the brewer. The stand alone operation goes into effect whenthe communication link is disconnected. The process begins at block 250and a determination is made as to whether the mode switch is at the runor program position at the block 252. If in the program position, theprocess is transferred to the program mode at block 254, while if theswitch is at the run mode, the receive, unit is checked for data on thecommunication link at block 256. At block 258, the determination is madeas to whether the communication link is connected, so that control istransferred to the interlocked operation as shown at block 260, orwhether the link is disconnected. If the communication link isdisconnected, the selector switches are checked for an input at block262 and, when the selection of a brew or grind cycle is made, asdetermined at block 264, the cycle is run at block 266. If the selectionof a brew or grind cycle is not made, the process returns to the block252 to again check the inputs. After the selected brew or grind cycle isrun, the process returns to initial block 250 so that another brew orgrind cycle may be run.

Thus, the control of the present invention provides either interlockedoperation or automatic switching to stand alone operation, as well as acalibration mode during set up.

Grinder Circuit

The control circuitry of the invention which carries out the functionsdescribed above and shown in the foregoing flowcharts is shown for anexemplary embodiment in detail in FIGS. 9, 10, 11 and 12. The controlcircuit for the grinder is shown in FIGS. 9 and 10. A broken outline inthe Figures indicates the control circuit and shows connections to theelements of the grinder unit, or brewer unit, respectively. Inparticular, the circuit includes a power input portion that includes atransformer that has a single primary winding 300 connected to an ACline power and two secondary windings 302 and 304. The first secondarywinding 302 supplies power to a constant current source for thecommunication link that includes a bridge rectifier 306, a filtercapacitor 308, a bleeder resistor 310, a resistor 312, a resistor 314, atransistor 316, a resistor 318, and two diodes 320 and 322. The powersupply circuit includes, in FIG. 9, a bridge rectifier 324, a diode 510,a filter capacitor 326, a bleeder resistor 328, a voltage regulator 330,a capacitor 332 and capacitor 334. A power-up reset circuit includes alow voltage detector 336, a pull-up resistor 338 and reset pin 340 of anintegrated circuit 342, which is a 68HC705J2 microcontroller chip.

As discussed above, the exemplary embodiment has two bins for coffee,each with an auger to move the beans to a grinder. Here, the two binsand their respective parts are referred to as regular, or reg, anddecaffeinated, or decaf, although other types of coffee may, of course,be placed in the bins. A decaf auger output is a port pin 344 of themicrocontroller chip 342, a base resistor 346, a pull-down resistor 348,a transistor 350 for driving a relay, a relay winding 352, and a diode354 across the winding. A filter capacitor 356 (FIG. 10) and the bridgerectifier 324 provide power to the relay winding. The armature of therelay winding 352 is connected to operate a switch 358 which appliespower to the decaffeinated auger 360 so that the beans in thedecaffeinated bin are moved to the grinder.

A regular auger output is controlled from a port pin 362 of themicrocontroller chip 342, through a base resistor 364 to a pull-downresistor 366, a transistor 368, a relay winding 370, and a diode 372,which is across the relay 370. A regular coffee auger 374 is switched onand off by the switch 376 of the relay winding 370, which moved theregular beans to the grinder.

The grind motor output is controlled from a port pin 378 of themicrocontroller chip 342. The control signals are transmitted through abase resistor 380 to a pull-down resistor 382 and a transistor 384 whichdrives a relay winding 386 across which is connected a diode 388. Theswitch 390 for the winding 386 has a MOV device 392 connectedthereacross. The switch 390 controls the operation of a grinder motor394, which drives the grinder (not shown). The grinder is turned on wheneither the decaf or the regular auger are operated.

A small decaf switch 396 is connected to an input of the presentcontrol, which input is connected to a half-wave rectifier 398, acurrent limiting resistor 400, a filter capacitor 402, and 1/7th of adarlington array amplifier 404a. A pull-up resistor 406 is provided atthe output of the amp 404a connected to a port pin 408 of themicrocontroller chip 342. A medium decaf switch 410 has a similararrangement including a half-wave rectifier 412, a current limitingresistor 414, a capacitor 416, 1/7th of the darlington array 404b, apull-up resistor 418 to a port pin 420 of the microcontroller 342. Alarge decaf switch 422 is connected through a half-wave rectifier 424, acurrent limiting resistor 426, a filter capacitor 428, 1/7th of thedarlington array 404c, a pull-up resistor 430 to a port pin 432 of themicrocontroller 342.

Connections of the selection switches to the microcontroller 342include, for a small regular switch 434, a half-wave rectifier 436, acurrent limiting resistor 438, a filter capacitor 440, 1/7th of thedarlington array 404d, a pull-up resistor 442 to a port pin 444 of themicrocontroller 342. A medium regular switch 446 is connected via ahalf-wave rectifier 448, a current limiting resistor 450, a filtercapacitor 452, 1/7th of the darlington array 404e, a pull-up resistor454 and a port pin 456 of the microcontroller 342. A large regularswitch 458 is connected through a half-wave rectifier 460, a currentlimiting resistor 462, a filter capacitor 464, 1/7th of the darlingtonarray 404f, a pull-up resistor 466 and a port pin 468 of themicrocontroller 342.

A PROG/RUN mode switch circuit includes a switch 470 (FIG. 10), apull-up resistor 472 and a port pin 474 of the microcontroller 342. Amicrocontroller oscillator circuit includes a ceramic resonator 476, aresistor 478, a pin 480 and a pin 482 of the microcontroller 342. Acommunication link transmit circuit includes a port pin 484 of themicrocontroller 342, 1/7th of the darlington array 404g, a opto-coupler486, a current limiting resistor 488, a resistor 490 and a transistor492. A communication link receive circuit includes an opto-coupler 494,a pull-up resistor 496 and a port pin 498 of the microcontroller 342. Anon-volatile memory circuit includes a port pin 500 of themicrocontroller 342, a pull-up resistor 502, a non-volatile memory 504and a port pin 506 of the microcontroller 342. A capacitor 508 is a highfrequency bypass capacitor for the microcontroller 342.

Circuit operation:

At power-up, the primary winding 300 of the transformer is energized.This primary winding 300 energizes the two separate secondaries 302 and304. The bridge rectifier 306 full-wave rectifies the voltage from thesecondary 302 which is then filtered by the capacitor 308 that becomesthe supply voltage for the constant current circuit. The constantcurrent source is set by the value of the resistor 318 with the voltagedrop across the resistor 318 being approximately one diode drop. Thediodes 320 and 322 in series is equal to two diode drops. Thebase-to-emitter diode drop is subtracted from these two diode drops,thus leaving the voltage drop across the resistor 318 equal toapproximately one diode drop. The resistor 314 limits the powerdissipation of the transistor 316. The resistor 312 supplies the basecurrent to bias the transistor 316. When the voltage across resistor 318exceeds approximately one diode drop, the transistor 316 turns offmaintaining constant current. The bridge rectifier 324 full-waverectifies the voltage from the secondary 304, which is,then filtered bythe capacitor 356 to become the source voltage for the relays 352, 370and 386. The voltage then passes through a diode 510 and is filtered bythe capacitor 326 and becomes the source voltage for the voltageregulator 330. The voltage regulator 330 regulates this voltage to avoltage level of +5 v which is used as the regulated supply for thecircuitry. A reset circuit holds the microcontroller line 340 low inreset until the +5 v supply is approximately 4.69 v, at which time theoutput of the reset circuit becomes an open circuit and the reset pin340 of the microcontroller 342 is pulled to +5 v through the resistor338. At this time, the microcontroller 342 begins to run. Themicrocontroller 342 then initialize all port pins. The port pins 344,362 and 378 are set as outputs and are low after power-up leaving therelays 352, 370 and 386 de-energized.

The port pins 408, 420, 432, 444, 456 and 468 are set as inputs and arehigh when a switch is not pressed. The port pin 474 is set as an inputand is high when the PROG/RUN mode switch 470 is in the PROG positionand low when the PROG/RUN switch is in the RUN position. The port pin484 is set as an-output and is high to close the current loop and low toopen the current loop (to transmit). The port pin 498 is set as an inputand is low when the current loop is closed and high when the currentloop is open (to receive). The port pin 500 is a bi-directional portpin. It is set as an output when sending data to the non-volatile memory504. It is set as an input when reading the non-volatile memory. Theport pin 506 is set as an output. It Is used when the pin 500 is anoutput to set-up a read or write sequence for the non-volatile memoryand to clock data in or out after the read or write operation as beeninitiated.

When the PROG/RUN mode switch 470 is in the RUN position (the pin 474 islow) and no grind cycles are pending, the microcontroller 342 waits fora low signal on one of the port pins used for the selector switch input(408 through 468) to initiate a cycle when a selector switch is pressed,the positive alternation of L1 with respect to L2 is rectified by thehalf-wave rectifier of the respective switch input and filtered by thecapacitor on the input of the darlington transistor 404 (represented bythe inverter symbol) turning it on. The output of the darlingtontransistor 404 goes low and the respective cycle is initiated. At thistime, the microcontroller 342 reads the stored timer value. The port pin378 goes high providing base current for the transistor 384 through theresistor 380. The transistor 384 turns on, energizing the relay 386. Ifthe selection was decaf, the pin 344 goes high providing base currentfor the transistor 350 through the resistor 346. The transistor 350turns on, energizing the relay 352. If the selected cycle was regular,the port pin 362 goes high providing base current for the transistor 368through the resistor 364. The transistor 368 turns on, energizing therelay 370.

After the time period for the selected cycle has elapsed, the port pinfor the respective auger output goes low removing the base current fromthe auger transistor to turn it off and, thus, de-energize the augerrelay. The pin 378 will remain high for an additional ten seconds atwhich time it goes low removing base current from the transistor 384 andturning it off, thereby de-energizing the grind motor relay 386.

The microcontroller 342 will now send the size signal on thecommunication link. The port pin 484 goes low for a durationrepresenting the sync pulse. The darlington transistor 404g connected tothe pin 484 turns off. No current flows through the input LED of theopto-coupler 486. The output transistor of the opto-coupler 486 turnsoff and no base current flows through the transistor 492. The transistor492 opens the current loop. When the pin 484 goes high, the darlingtontransistor 404g connected to the pin 484 turns on. Current flows throughthe input LED of the opto-coupler 486. The output transistor of theopto-coupler 486 turns on allowing base current through the transistor492. The transistor 492 turns on, closing the current loop. After thesync pulse has been sent, the microcontroller 342 waits for a period oftime then sends the size signal by opening the current loop aspreviously described. After the size signal has been sent, themicrocontroller 342 waits for a further period of time. After thisfurther time has elapsed, the controller 342 looks for a response from abrewer, of which there may be several in the loop, on the communicationlink. If a response is not received, the grinder control transmits againas previously described.

A brewer responds by opening the current loop. The microcontroller 342senses that the current loop is open via the opto-coupler 494. When thecurrent loop is closed, the input diode of the opto-coupler 494 is on.The transistor of the opto-coupler 494 is on, pulling the port pin 498of the microcontroller 342 low. When the current loop is open, the inputdiode of the opto-coupler 494 is off. The transistor of the opto-coupler494 is off (an open circuit) and the port pin 498 of the microcontroller342 is pulled high through the resistor 496. When the response isreceived from the brewer or when the current loop is always open, a newgrind cycle can begin.

When the PROG/RUN switch 470 is in the PROG position, i.e. is open, theport pin 474 is pulled high through the resistor 472. The grind time isprogrammed by pressing and holding the selector switch for the desiredtime. The grind relay 386 and the selected auger relay 352 or 370activate as previously described. When the selector switch is released,the selected auger relay will turn off as previously described and thegrind motor relay 386 remains on for an additional ten seconds aspreviously described.

When the PROG/RUN mode switch 470 is placed in the RUN position (isclosed), the microcontroller 342 stores the count in the non-volatilememory 504. The port pins 500 and 506 of the microcontroller 342 areoutputs. After the write sequence is initiated, the serial data is senton the port pin 500 and clocked into the non-volatile memory 504 by theport pin 506 and the microcontroller 342.

Brewer Circuit

FIGS. 11 and 12 show the detailed circuitry of the brewer control. Thepower supply circuit includes a half-wave rectifier 520, currentlimiting resistors 522 (which is a cuttable trace for use as a 240 Vunit) and 524, a filter capacitor 526, a high frequency bypass capacitor528, a bleeder resistor 530, a zener diode 532, a voltage regulator 534,a capacitor 536 and a capacitor 538. A small switch 539 is input througha half-wave rectifier 540, a current limiting resistor 544, a filtercapacitor 542, 1/7th of a darlington array 546a, a pull-up resistor 548,a capacitor 550, a resistor 552, a diode 554, to a pin 556 of amicrocontroller 558 and a port pin 560 of the microcontroller 558. Amedium switch 561 is input through a half-wave rectifier 562, a currentlimiting resistor 564, a filter capacitor 566, 1/7th of the darlingtonarray 546b, a pull-up resistor 568, a capacitor 570, the resistor 552,the diode 554, to the pin 556 of the microcontroller 558 and a port pin572 of the microcontroller 558. A large switch 573 is input through ahalf-wave rectifier 574, a current limiting resistor 576, a filtercapacitor 578, 1/7th of the darlington array 546c, a pull-up resistor580, a capacitor 582, the resistor 552, the diode 554, to the pin 556 ofthe microcontroller 558 and a port pin 583 of the microcontroller 558.

A small lamp circuit includes a port pin 584 of the microcontroller 558,a base resistor 586, a transistor 588 and. a half-wave rectifier 590connected to a small indicator lamp 592 of the brewer. A medium lampcircuit includes a port pin 594 of the microcontroller 558, a baseresistor 596, a transistor 598 and a half-wave rectifier 600 connectedto a medium indicator lamp 602 of the brewer. A large lamp circuitincludes a port pin 604 of the microcontroller 558, a base resistor 606,a transistor 608 and a half-wave rectifier 610 connected to a largeindictor lamp 612.

A first water solenoid output includes a port pin 640 of themicrocontroller 558, 1/7th of the darlington array 546d, a base pull-upresistor 616, a diode 618, a transistor 620, a relay winding 622, afilter capacitor 624 connected across the relay, current limitingresistors 626 (for a 240v model) and 628, a half-wave rectifier 630 anda half-wave rectifiers 632 (from the small switch 539), 634 (from themedium switch 561) and 636 (from the large switch 573). These elementsare connected to control a water solenoid 638 that operates the watercontrol valve of the brewer.

A second water solenoid output includes a port pin 614 of themicrocontroller 558, 1/7th of the darlington array 546e, a base pull-upresistor 642, a diode 644, a transistor 646, a relay 648, a filtercapacitor 650, current limiting resistors 652 (for a 240 V model) and654, the half-wave rectifier 630 and the half-wave rectifiers 632 (fromthe small switch input), 634 (from the medium switch input) and 636(from the large switch input).

A PROG/RUN mode switch circuit includes a mode switch 656, a pull-upresistor 658 and port pin 660 of the microcontroller 558. A power-upreset circuit includes a low voltage detector 662, a pull-up resistor664, a capacitor 666 and a reset pin 667 of the microcontroller 558. Amicrocontroller oscillator circuit includes a ceramic resonator 668, aresistor 670, a pin 672 of the microcontroller 558 and a additional pin674 of the microcontroller 558.

A communication receive circuit includes an opto-coupler 676, a pull-upresistor 678 and a port pin 680 of the microcontroller 558. Acommunication transmit circuit includes a port pin 682 of themicrocontroller 558, 1/7th of the darlington array 546f, a diode 684, anopto-coupler 687, a resistor 688, a filter capacitor 670, a currentlimiting resistor 672, a resistor 674, a resistor 676 and a transistor678.

A non-volatile memory circuit includes a port pin 681 of themicrocontroller 558, a pull-up resistor 682, a non-volatile memory 684and a port pin 686 of the microcontroller 558. A capacitor 689 is a highfrequency bypass capacitor for the microcontroller 558.

Circuit operation:

At power-up, the positive alternation of L1 with respect to L2 isrectified by the half-wave rectifier 520. The current is limited by theresistors 522 (for 240 v unit) and 524. The voltage is filtered by thecapacitor 526 and becomes the source voltage for the voltage regulator534. The zener diode 532 clamps the voltage to a safe level for theinput of the voltage regulator 534 should the line voltage get too high.The output of the voltage regulator 534 is regulated to +5 v for thecircuitry.

The reset circuit holds the microcontroller reset line 667 low until the+5 v supply is approximately 4.69 v, at which time the output of thereset circuit 662 becomes an open circuit and the reset pin 667 of themicrocontroller 558 is pulled to +5 v through the resistor 664. At thistime, the microcontroller 558 begins to run. The microcontroller 558then initialize all port pins. Port pins 614 and 640 are set as outputsand are high after power-up, turning off the relay drive circuitry. Theport pins 604, 594 and 584 are set as outputs and are low afterpower-up, turning off the lamp outputs. The port pin 682 is set as anoutput and is low after power-up, closing the current loop. The port pin680 is a bi-directional port pin. It is an output when sending data tothe non-volatile memory 684. Alternately, it is set as an input whenreading the non-volatile memory.

The port pin 686 is set as an output. It is used when the pin 680 is anoutput to set-up a read or write sequence for the non-volatile memory684 and to clock data in or out after the read or write sequence hasbeen initiated. The port pins 560, 572 and 583 are set as inputs. Theyare high when a selector switch is not pressed and low when a selectorswitch is pressed. The port pin 660 is set as an input and is high whenthe PROG/RUN mode switch 656 is in the PROG position and low when thePROG/RUN switch is in the RUN position. The port pin 681 is set as aninput and is high when the current loop is open and low when the currentloop is closed. The port pin 692 is set as an input and is pulled highthrough a resistor 690. This port pin 692 is not being used.

When the PROG/RUN switch 656 is in the RUN position, the microcontroller558 watches the port pin 680 of the microcontroller 558 to see if thecurrent loop is open for more than one second. If the current loop hasbeen open for more than one second, the control operates as astand-alone unit. If the current loop has not been open for more thanone second, the control operates in the interlock mode.

In the interlock mode, the microcontroller looks at the port pin 680 forthe sync pulse from the grinder, followed by the size signal (refer toFIG. 13 for the serial communications protocol for the grinder). If thesize signal is a "no beans pending" signal, a brew cycle is not allowed.If the size signal is small size pending, the microcontroller will turnon the small lamp. The port pin 584 of the microcontroller 558 will gohigh, providing base current for the transistor 588 through the resistor586. The transistor 588 turns on. The positive alternation of L1 withrespect to L2 is rectified by the half-wave rectifier 590 and the smalllamp will light. At this time, the microcontroller 558 looks at the portpin 680 to read the current loop. If the size signal is equal to the "nosize pending" signal, or the current loop has been open for more thanone second, the port pin 584 of the microcontroller 558 will go lowremoving the base current to transistor 588 turning off the lamp. If thesize signal is still equal to the "small size pending" signal, the portpin 584 will remain high (the lamp on). The microcontroller watches theport pin 560 for the allowed cycle to be initiated. All other selectorswitch inputs are locked-out. When the small selector switch is pressed,the positive alternation of L1 with respect to L2 will be rectified bythe half-wave rectifier 632, becoming the source voltage for the relay622. The positive alternation of L1 is rectified by the half-waverectifier 540. The current is limited by the resistor 542 and filteredby the capacitor 544 becoming the source voltage for the darlingtontransistor (represented by an invertor symbol). The darlingtontransistor then turns on, pulling the port pin 560 of themicrocontroller 558 low. A low going pulse is sent to the 556 line ofthe microcontroller 558. This pulse is used to "wake-up" themicrocontroller should the program lock-up due to electrical noise. Whenthe microcontroller senses the pin 560 is low, the current loop is readagain. Following the next size signal, the acknowledgement signal issent (as will be described later in conjunction with FIG. 13). The portpin 682 goes high turning on the darlington transistor. The anode of theopto-coupler 686 is pulled to circuit ground, turning off the LED of theopto-coupler 686. The output transistor of the opto-coupler 686 turnsoff the base current to the transistor 678. The transistor 678 turns offand opens the current loop, thus, sending the acknowledgement pulse.When the acknowledgement is finished, the port pin 682 of themicrocontroller 558 goes low turning off the darlington transistor. Theoutput of the darlington transistor becomes open circuit and theopto-coupler LED turns on through resistor 688. The output transistor ofopto-coupler 686 turns on, allowing base current to flow to thetransistor 678. The transistor 678 turns on and the current loop is nowclosed. After the acknowledgement is sent, the microcontroller reads thetimer value from the non-volatile memory 684. The serial data is read inon the port pin 681 (input) of the microcontroller 558 and clocked bythe port pin 686 (output) of the microcontroller 558. At this time, themicrocontroller turns on the water output. The port pin 640 of themicrocontroller 558 goes low, turning off the darlington transistor. Theoutput of the darlington transistor becomes an open circuit, allowingbase current for the transistor 620 to flow through the resistor 616.The transistor 620 turns on, energizing relay 622. The capacitor 624filters the voltage across the relay 622. The current to the relay 622is limited by the resistors 626 (for 240 v units) and 628. When thecontacts of the relay 622 transfer, the line voltage is now latched andrectified through the half-wave rectifier 630. During the brew cycle,the small lamp output will flash by the port pin 584 going high and low.After the brew time has elapsed, the port pin 640 of the microcontroller558 goes high. The darlington transistor turns on. The output of thedarlington transistor goes low, removing the base current from thetransistor 620. The collector of transistor 620 becomes an open circuitand the relay 622 de-energizes. The port pin 584 continues going highand low flashing the lamp output for an additional 90 seconds. After 90seconds, the port pin 584 goes low removing base current from thetransistor 588. The collector of transistor 588 open circuits and thelamp turns off. During the 90 second flash time, any new brew cycles arenot allowed.

A medium and large brew cycle will operate in the same manner usingtheir respective switch inputs and lamp outputs with one exception. Thelarge brew cycle turns on the water output and the bypass output.

In the stand-alone operation, a new brew cycle can be started any timeafter the current cycle has finished. When the port pin 660 is high (asa result of the PROG/RUN mode switch being open), the microcontrollerinitiates the program mode. The port pins 604, 594 and 584 go high andlow flashing all three lamp outputs. A momentary start switch closureturns on the outputs and only the lamp output for the selection beingprogrammed will flash. A small program cycle turns on the water outputonly. A medium program cycle turns on the water output only. A largeprogram cycle turns on the water output and the bypass output. Themicrocontroller starts a counter. When the desired program time isreached, a momentary closure of the start switch terminates the programcycle and the outputs turn off and the microcontroller stops thecounter. All lamp outputs will now flash. If other selections requireprogramming, repeat the process.

When all selections have been programmed, the PROG/RUN mode switch isplaced in the RUN position (the switch is closed). The port pin 660 ispulled low. The microcontroller then saves the counter values in thenon-volatile memory 684. The data is sent by the port pin 681 of themicrocontroller 558 and clocked into the non-volatile memory by the portpin 686 of the microcontroller 558. The port pins 604, 594 and 584 golow, turning off the lamp outputs. The microcontroller now returns torun mode.

Signal Diagram

The signals appearing on the communication link for the present circuitare shown in FIG. 13. The overall communication protocol for informationexchange between the grinder and brewer provides that the grindercontrol transmits a synchronization pulse on the communication link,followed by a pulse that indicates the quantity of coffee beans whichhave been ground, or indicates that there have been no beans ground. Ata predetermined time after the synchronization pulse, the grindercontrol checks the communication link for an acknowledgement from thebrewer control that the corresponding brew cycle has been initiated.

In detail, as shown in FIG. 13, the first signal shown is the "no beanspending" signal, which has a synchronization pulse in the first pulseframe followed by a long pulse in the second pulse frame. Following thesecond pulse frame, the broken line indicates the frame that is checkedfor the acknowledgement from the brewer. At some time after theacknowledgement frame, the same signal sequence is repeated until theacknowledgement is received.

In the second signal of FIG. 13, the synchronization is followed by nopulse in the second frame, in other words, the level remains at "0"during the time that the brewer is checking for a size signal. Thisindicates that a small size grind has been selected in the grinder. Thelow or "0" signal level indicates that the current loop of thecommunication link is closed, while a high or "1" indicates that theloop is open.

The third signal indicates a medium size grind by the grinder. Followingthe synchronization pulse, the second pulse frame has a high or "1"signal which then goes low or to "0" for the second half of the secondsignal frame. The fourth signal, accordingly, indicates a large sizegrind cycle by the grinder, wherein the second pulse frame is initiallylow and goes high or to "1" at the mid point of the second frame.

The last signal shown is the signal, emitted by the brewer after thecorresponding brew cycle has been selected. The brewer control transmitsan acknowledgement pulse, as shown, on the communication link at thetime indicated by the broken lines, which is the acknowledgement frame.

In an exemplary embodiment, the synchronization pulse and the secondpulse frame are each 82 ms in length with 41 ms between them. Theacknowledgement frame is approximately 230 ms from the start of thesynchronization pulse and extends for 8.2 ms. Of course, other signalprotocols can be used to convey the necessary information.

Alternate uses

The present control may be used to connect the controls of any two ormore related units, for example, an ice crusher/dispenser and a colddrink dispenser which are controlled so that the proper quantity of iceis crushed and/or dispensed for the capacity of cold drink to bedispensed. Coffee grinders may be linked to espresso machines forespresso, milk dispensers/steamers may be linked to espresso machinesfor cappaccino, batter mix dispensers may be linked to controlledquantity water dispensers, etc. with controls according to the presentinvention. Many other uses interconnecting two related devices arepossible as well.

Although other modifications and changes may be suggested by thoseskilled in the art, it is the intention of the inventors to embodywithin the patent warranted hereon all changes and modifications asreasonably and properly come within the scope of their contribution tothe art.

We claim:
 1. A method for calibrating a coffee grinder for automaticoperation, comprising the steps of:setting a control for the coffeegrinder to a calibrate mode; initiating grinding operations of thecoffee grinder; halting said grinding operation when a predeterminedquantity of ground coffee has been produced during said grindingoperation at a now defined time from said initiation step; and settingsaid control to a normal run mode which automatically operates thecoffee grinder for said now defined time.
 2. A method for calibrating acoffee grinder for automatic operation, comprising the stepsof:initiating grinding operations of the coffee grinder; halting saidgrinding operation when a predetermined quantity of ground coffee hasbeen produced during said grinding operation at a now defined time fromsaid initiation step; and setting said control to a normal run modewhich automatically operates the coffee grinder for said now definedtime.